Cinematographic apparatus

ABSTRACT

A motion picture camera or projector wherein the rotor of an electric motor constitutes the shutter. The motor has a flat housing a portion of which is located between the picture taking lens and the light-admitting opening of a film guide and has a second opening which admits scene light from the lens to the opening of the guide or vice versa in predetermined angular positions of the shutter. The shutter is rigid with a cam which actuates the claw pull-down.

[75] Inventor:

United States Patent [191 I Steppi CINEMATOGRAPHIC APPARATUS HubertSteppi, Garching, Germany [73] Assignee: Agfa-GevaertAktiengesellschaft,

Leverkusen, Germany [22] Filed: June 23, 1972 [21] Appl. No.: 265,776

[30] Foreign Application Priority Data Sept. 17, 1971 Germany P 21 46526.9

[52] US. Cl. 352/166 [51] Int. Cl. G03b 1/22, G03b 19/18 [58] Field ofSearch 352/166 [56] References Cited UNITED STATES PATENTS 3,428,3942/1969 Wessner 352/166 Oct. 30, 1973 Primary Examiner-Samuel S. MatthewsAssistant Examiner-Russell E. Adams, Jr. Attorney-Michael S. Striker[57] ABSTRACT A motion picture camera or projector wherein the rotor ofan electric motor constitutes the shutter. The motor has a flat housinga portion of which is located between the picture taking lens and thelight-admitting opening of a film guide and has a second opening whichadmits scene light from the lens to the opening of the guide or viceversa in predetermined angular positions of the shutter. The shutter isrigid with a cam which actuates the claw pull-down.

10 Claims, 3 Drawing Figures 1 CINEMATOGRAPl-IIC APPARATUS BACKGROUND OFTHE INVENTION The present invention relates to cinematographic apparatusin general, and more particularly to improvements in electric motors foruse in motion picture cameras or projectors.

It is already known to utilize in a cinematographic apparatus a d-cmotor which servesas a means for rotating the shutter and/or foractuating the film transporting mechanism. As a rule, the rotationalspeed of the output shaft of the d-c motor is much higher than thedesired speed of the shutter so that the cinematographic apparatus mustemploy a step-down transmission which is interposed between the outputshaft of the motor and the shutter. The shaft which drives the shutternormally also serves to transmit motion to the film transportingmechanism which can employ a conventional claw pull-down.

It was further proposed to utilize in a cinematographic apparatus anelectric motor whose rated RPM 1 is sufficiently low to allow for themounting of shutter directly on the output shaft of the motor. Forexample, if the output shaft of the motor rotates at 1,080 RPM, thiscorresponds to a frequency of 18 frames per second. An advantage of suchproposal is that the transmission can be omitted with attendantreduction in noise and lower cost of the cinematographic apparatus.Noiseless or quiet operation of a motion picture camera is particularlyimportant if the camera is equipped with sound recordingmeans, a featurewhich is becoming increasingly popular even in moderately priced motionpicture cameras. A drawback of presently knownelectric motors which canrotate their output shafts at the RPM which is satisfactory for directmounting of the shutter thereon is that their casings are much too bulkyfor incorporation in the housing of a compact motion picture camera.This is due to the fact that the plane of film transport is closelyadjacent to the picture taking lens so that there is no room for themounting of a conventional motor in such a way that the shutter can bemounted directly on the output shaft of the motor and is still capableof controlling the passage of scene light from the lens to successiveunexposed film frames. Also, the presently known cinematographicapparatus which employ a shutter mounted directly on the output shaft ofthe motor must utilize a largediameter shutter because the casing of themotor cannot be inserted between the lens and that film frame whichregisters with the lens.

SUMMARY OF THE INVENTION An object of the invention is to provide amotion picture camera or a motion picture projector with a novel andimproved prime mover, preferably an electric motor, which occupies solittle room and rotates its output shaft at such a speed that the outputshaft can directly support the shutter and that such shutter can controlthe passage of light between the picture taking lens and successive filmframes or vice versa.

Another object of the invention is to provide a cinematographicapparatus which embodies the improved prime mover and whose housing ismore compact than the housings of conventional cinematographicapparatus.

A further object of the invention is to provide a cinematographicapparatus wherein the prime mover can drive the shutter and/or the filmtransporting mechanism without the interposition of a transmission sothat the apparatus is less expensive and produces less noise thanheretofore known cinematographic apparatus.

An additional object of the invention is to provide a novel and improvedcasing for the motor which drives the shutter and/or the filmtransporting mechanism in a motion picture camera or motion pictureprojector.

The invention is embodied in a cinematographic apparatus which comprisesa housing, a picture taking lens which is mounted in the housing, a filmguide which is mounted in the housing behind the picture taking lens,and an electric motor (preferably a d-c motor) having a flat casingwhich is preferably of circular outline and includes a flat portionlocated between the film guide and the picture taking lens, alight-admitting opening provided in such casing portion in register withthe picture taking lens and with a light-admitting opening of the filmguide, and a rotor which is mounted directly on the output shaft of themotor and constitutes a shutter which is arranged to periodically allowlight passing through the picture taking lens to reach the film which isguided by the film guide, or vice versa. The rotor is preferably a flatdisk having a preferably segmentshaped aperture which registers with theopenings of the motor casing and film guide during a predeterminedportion of each revolution of the rotor.

The rotor is preferably rigid with an eccentric cam or analogousactuating means for a claw pull-down or analogous film transportingmeans. The RPM of the rotor is such that the cinematographic apparatuscan admit scene light to a desired number of film frames per unit oftime or that the light which passes through successive frames of exposedand developed film canpass through the lens of a projector at a desiredfrequency.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved cinematographic apparatus itself, however, both as to itsconstruction and its mode of operation, together with additionalfeatures and advantages thereof, will be best understood upon perusal ofthe following detailed description of certain specific embodiments withreference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary perspectiveview of portion of a cinematographic apparatus which embodies theimproved electric motor;

FIG. 2 is a sectional view of the motor and of the film guide; and

FIG. 3 is a sectional view as seen in the direction of arrows from theline IIIIII of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS movable front portion 5. Theprism 4 directs a portion of incoming scene light into the view finderand/or against a suitable photosensitive receiver, not shown. The filmguide 1 is further provided with a vertical slot 1b for the claw a (seeFIG. 2) of a reciprocable film transporting member here shown as aconventional claw pull-down 10. I

In accordance with a feature-of the invention, the housing H of themotion picutre camera further accommodates an electric motor 6 having anovel flat casing 6A of circular outline. The upper portion of thecasing 6A extends into the narrow space between the rear portion 3 ofthe picture taking lens and the front side of the film guide 1 and isprovided with a light-admitting or light-transmitting opening 6a inregister with the lens and with the opening la. The right-hand axial endof the casing 6A, as viewed in FIG. 2, can be mounted directly on thefilm guide 1 and the central portion or dome of the casing 6A can bemounted in the housing H so that the casing is located in apredetermined position relative to the parts 1 and H. The rotor 7 of themotor 6 is a flat disk which constitutes the shutter of the motionpicture camera and has a segment-shaped the output shaft 8 of the motor6, and since the output.

shaft 8 further directly supports the cam 9, the motion I picture cameraneed not embody a transmission which brings about substantial savings ininitial cost, savings in time for assembly of the apparatus, savings inspace, and a substantial reduction of noise.

The pull-down 10 is biased against the periphery of the cam 9 by asuitable spring, not shown. If desired, the actuating means for thepull-down 10 may comprise two cams one of which serves to positivelymove the pull-down in a first direction and the other of whichpositively moves the pull-down in the opposite direction. The in-and-outmeans for the claw 10a of the pulldown 10 is not shown in the drawingbecause its construction forms no part of the present invention.

It is clear that the improved cinematographic apparatus is susceptibleofmany additional modifications. For

example, the motor 6 can be used with equal advantage in a motionpicture projector. Also, the apparatus may embody a suitable diaphragmwhich can be mounted in the front portion 5 or in the rear portion 3 ofthe picture taking lens.

As best shown in FIG. 2, the height (as considered in the direction ofoptical axis X-X) of that portion of the flat casing 6A which is locatedin the narrow space between the rear portion 3 of the lens and the filmguide 1 is only a small fraction of the diameter or maximum dimension ofthe casing 6A. Also, the overall axial length of the casing 6A ispreferably less than its diameter; this renders it possible toaccommodate the casing 6A in the housing H of a small portable motionpicture camera and/or in the housing of a compact motion pictureprojector. The entire rotor 7 is preferably concealed in the interior ofthe casing 6A. The height of that portion of casing 6A which is locatedbetween 4 the rear portion 3 of the lens and the film guide 1 is lessthan the focal length of the lens, and the radius of the housing 6Asubstantially exceeds the width of the film 2. The exact dimensions ofthe casing 6A are normally selected in dependency on the focal length ofthe lens, the type of film used and certain other factors.

The exact construction of those components of the motor 6 which rotatethe rotor 7 when the circuit of the motor is completed forms no part ofthe invention. FIG. 1 merely shows two conductors which can be connectedto the respective poles of an energy source in response to closing of asuitable switch, not shown.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featureswhich fairly constitute essential characteristics of the generic andspecific aspects of my contribution to the art and, therefore, suchadaptations shouldand are intended to be comprehended within the meaningand range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended 1. In a cinematographic apparatus, acombination comprising a housing; a lens mounted in said housing; a filmguide mounted in said housing behind said lens; and an electric motorcomprising a flat casing including a portion disposed between said lensand said film guide andhaving light-transmitting opening means inregister with said lens and with the film in said film guide so that, inthe absence of 'an obstruction between said lens and said film guide,scene light entering said housing by way of said lens can impinge on thefilm in said film guide, said motor further comprising a rotor mountedin said flat casing and having a portion which normally interceptsscene, light passing through said lens so that such light cannot reachthe film in said film guide, said portion of said rotor being arrangedto periodically allow scene light to pass through said opening means andto reach the film in said film guide in response to rotation of saidrotor.

2. A combination as defined in claim 1, wherein said portion of saidrotor is a flat disk having an aperture which registers with saidopening means during a pre- 7 determined portion of each revolution ofsaid rotor.

3. A combination as defined in claim 1, wherein said casing is of atleast substantially circular shape.

4. A combination as defined in claim 1, further comprising filmtransporting means actuatable to transport the film relative to said'film guide and actuating means connected for rotation with said rotorand arranged to actuate said film transporting means.

5. A combination as defined in claim 4, wherein said film transportingmeans comprises a reciprocable claw pull-down.

. 6. A combination as defined in claim 5, wherein said actuating meanscomprises cam means.

1 7. A combination as defined in claim 4, wherein said rotor furthercomprises a rotary shaft rigid with said actuating means.

8. A combination as defined in claim 7, wherein said shaft is journalledin said film guide.

9. A combination as defined in claim 1, wherein said film guide has anopening in register with said opening means of said portion of saidcasing, said portion of said rotor being disposed in a plane which isnormal to the axis of said lens.

10. A combination as defined in claim 1, wherein said motor is a d-cmotor.

1. In a cinematographic apparatus, a combination comprising a housing; alens mounted in said housing; a film guide mounted in said housingbehind said lens; and an electric motor comprising a flat casingincluding a portion disposed between said lens and said film guide andhaving light-transmitting opening means in register with said lens andwith the film in said film guide so that, in the absence of anobstruction between said lens and said film guide, scene light enteringsaid housing by way of said lens can impinge on the film in said filmguide, said motor further comprising a rotor mounted in said flat casingand having a portion which normally intercepts scene light passingthrough said lens so that such light cannot reach the film in said filmguide, said portion of said rotor being arranged to periodically allowscene light to pass through said opening means and to reach the film insaid film guide in response to rotation of said rotor.
 2. A combinationas defined in claim 1, wherein said portion of said rotor is a flat diskhaving an aperture which registers with said opening means during apredetermined portion of each revolution of said rotor.
 3. A combinationas defined in claim 1, wherein said casing is of at least substantiallycircular shape.
 4. A combination as defined in claim 1, furthercomprising film transporting means actuatable to transport the filmrelative to said film guide and actuating means connected for rotationwith said rotor and arranged to actuate said film transporting means. 5.A combination as defined in claim 4, wherein said film transportingmeans comprises a reciprocable claw pull-down.
 6. A combination asdefined in claim 5, wherein said actuating means comprises cam means. 7.A combination as defined in claim 4, wherein said rotor furthercomprises a rotary shaft rigid with said actuating means.
 8. Acombination as defined in claim 7, wherein said shaft is journalled insaid film guide.
 9. A combination as defined in claim 1, wherein saidfilm guide has an opening in register with said opening means of saidportion of said casing, said portion of said rotor being disposed in aplane which is normal to the axis of said lens.
 10. A combination asdefined in claim 1, wherein said motor is a d-c motor.